I am going to be replacing my injection pump soon and was going to pull the vacuum pump off and replace the seal and the o-rings since its so much easier with the injection pump out of the way. Can both of these pumps be taken off without causing issues with the injection pump drive gear? When the injection pump is taken out, the gear is left in the front cover and the new pump shaft is pushed back into it with the new key. Then I heard that the vacuum pump gear is driven by the injection pump gear......

So my question is, does this vacuum pump gear hold the injection pump gear in place when the injection pump is removed or will the injection pump gear stay in place with the vacuum pump removed?

 

No it doesn't, not all B series engine run anything at the acc. drive position, the Cam gear is what drives the Inj. gear, and the case would keep it from falling.

Pulling the vacuum pump isn't a huge thing even with the pump in place though....

 

Ya, I know it will come out with it in place, but I have to replace the injection pump anyway and didn't want to pull the injection pump out and have the gear drop down in the front case and have to retrieve it. I was hoping that with the vacuum pump gear out everything else would stay in place....

 

As long as you don't rotate the crankshaft, you'll be fine with the injection pump. I don't think there is any way for the gear to fall down into the case. A small bolt or the pump shaft key will drop down inside, so be careful there.

The vacuum pump doesn't care what position it's in when it is put back in. The camshaft gear drives both the accessory gear (vacuum pump) and the injection pump gear separately.

 

Vac gear is driven by camshaft gear so no problem.

 

Sorry to hijack but for those that have pulled the pump with the engine still in the truck, did you have issues separating the pump from the motor? I removed all the bolts and it wouldn't budge. I didn't want to beat on it for fear of breaking the case. Any suggestions?

 

If you mean the whole assembly, did you get the brace from the PS pump to the block out?

If you mean the PS pump to the vacuum pump, sometimes the spacers stick...... a light tap ( LIGHT! ) can help break them loose.

 

When I pulled mine it came out fairly easily. I pulled the entire assembly. Once you pull the hydraulic lines, vacuum line, oil supply line, the two nuts holding it to the timing case, and the pump brace, it should come out. May have to wiggle it off of the cam gear but it will come out.

I don't reccomend separating the two pumps in the engine compartment. I did that and ended up having to do it twice. The second time I pulled the entire assembly. It's really hard to line the two pumps back up without knocking the vacuum pump seal loose.

 

quick update. I did forget the little bracket. I finally got it out and fixed they seal leak and a leak I had coming from the power steering pump. I agree with taking it out as a unit. I don't know how anyone gets that nut off on the block side.